Physical Computing - Three Controllers for KS2

controllers Codebug CodeBug is a cute, programmable device designed to introduce simple programming and electronic concepts to anyone, at any age. CodeBug can display graphics and text and has two push buttons and six crocodile clip rings for inputs and outputs. Being small and powered by a watch battery it makes wearable tech projects a real possibility for the KS2 classroom.

The Codebug is easy to program. It uses an online interface, which features colourful drag and drop blocks very similar to Scratch. And like Scratch there’s an in-browser emulator so that you can test your program before you download it to the CodeBug. It’s also programmable in Python. The Codebug website provides lots of ideas and tutorials for projects (though a few more that don’t involve using a Raspberry Pi would be great).


The online user community actively encourages users to use, adapt and share project ideas. There’s also a nice online badge reward system for anyone completing and remixing activities and answering or posing questions in the forum. The only thing to beware of with Codebug is that it’s quite difficult inserting and removing the battery, and little hands might find the exposed LEDs and metalwork rather sharp. Price: £12.50 each from:

Crumble Controller The Crumble is a cheap, easy-to-use electronics controller. A few ‘croc’ leads and a USB cable are all you need to connect motors, LEDs and sensors and begin experimenting. It’s the same size as the CodeBug but the 3x1.5v AA battery pack means it’s a little less wearable. However, its use of a slightly higher voltage does mean that the Crumble can drive two motors making it ideal for attaching to a buggy or powering a chain of up to 32 ‘sparkles’. (A sparkle is a special LED that actually contains red, blue and green emitters. The Crumble can be programmed so that each sparkle displays a different colour.)

The Crumble lacks Codebug’s bank of embedded LEDs but a series of add-ons or ‘Crumbs’ are in the pipeline that will allow text display and sound. A temperature sensor input is also planned. The Crumble is programmed using a free-to-download desktop application very similar to Scratch. Redfern Electronics, manufacturer and distributor of the Crumble, provides a great ‘getting started’ guide, a blog and a support forum. The site is a little more grown up, less child friendly than Codebug but shouldn’t be too intimidating for the novice KS2 electronics teacher. There aren’t too many project guides available yet but the Crafty Crumble Creations from Helen Roberts are fabulous! Price: £10 for the basic Crumble Controller.

The Crumble starter kit is great value and saves a frustrating trip to your local electronics store; it is £20 from:

GEMMA The GEMMA from Adafruit is another controller that is small enough to use in wearable projects. Like the Crumble and Codebug it has sewing friendly pads to attach it to fabric and other electronic components such as NeoPixels (similar to Sparkles) and sequins (LEDs) with crocodile clips or conductive thread. External power is provided via 3 x AAA batteries, 2 x 3032 coin batteries or the super light Lithium Polymer ‘Lipoly’ battery. The GEMMA is programmed via a miniB USB cable using the free-to-download Arduino IDE, providing a great opportunity to move pupils on from a ‘block based graphical’ programming environment to a text based programming environment. For teachers not familiar with coding in Arduino IDE, there are lots of guides and some great project ideas available on the Adafruit website: Priced at £7.99 from: or a starter kit for £21.67 plus p&p from:

We love all three controllers and each has its advantages. The Codebug and Crumble have Scratch-like programming environments allowing pupils and teachers to move easily from controlling an on screen spirit to controlling physical systems. The Crumble and its 3 x AA batteries is too bulky for most wearable projects but the arrival of add-on crumbs will extend the range of potential uses. The tiny GEMMA is great for wearable projects and is a nice way to introduce pupils already familiar with physical computing to a text based programming language.

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